Material for deaerating coating systems

Abstract

An aqueous composition for coating substrates which contains polymeric organic film formers containing a deaerating effective amount of a linear polymer having at least five side groups, each of which contains a silicon atom which is linked by way of a divalent hydrocarbon group to the polymer, each silicon atom carrying at least one R 1 group of formula O--[C.sub.n H.sub.2n O--].sub.x Q in which n is 2 to 8, x is 1 to 10 and Q is an alkyl radical with 1 to 10 carbon atoms, an aryl radical, an alkaryl radical, or an acyl radical with 2 to 18 carbon atoms, and the sum of the carbon and oxygen atoms of R 1 is not less than 5, as well as the linear polymers themselves. Methods for preparation of such materials are also disclosed as well as their use.

We claim: 
     
       1. In an aqueous phase coating composition which contains polymeric, organic film formers, the improvement which comprises said composition containing a deaerating effective amount of a linear polymer having at least five side groups, each of which contains a silicon atom which is linked by way of a divalent hydrocarbon group to the polymer, each silicon atom carrying at least one R 1  group of formula   O--[C.sub.n H.sub.2n O--].sub.x Q     in which   n is 2 to 8,   x is 1 to 10 and   Q is an alkyl radical with 1 to 10 carbon atoms, an aryl radical, an alkaryl radical, or an acyl radical with 2 to 18 carbon atoms, and the sum of the carbon and oxygen atoms of R 1  is not less than 5.     
     
     
       2. The composition of claim 1 wherein the linear polymer has lateral structural units linked to it having the formula ##STR24## in which R 2  and R 3  are the same or different and represent a CH 3  -- or C 2  H 5  -radical, a lower alkoxy radical with 1 to 6 carbon atoms or the R 1  radical, and R 4  is a hydrogen or methyl radical.   
     
     
       3. The composition of claim 2 wherein the linear polymer has the formula ##STR25## in which M is a chain-forming monomer unit, Z is a terminating group,   u is not less than 5, and the quotient u/v is not less than 0.4.   
     
     
       4. The composition of claim 1, 2, or 3, which further contains hydrophobic, finely divided silica, having a BET surface area of at least 50 m 2  /g in amounts of 30 weight percent, based on the weight of the composition. 
     
     
       5. The composition of claim 2 wherein the linear polymer has the formula ##STR26## wherein R 5  and R 6  are the same or different and represent an alkyl, phenyl or hydrogen radical, in which not more than 10 mole percent of all silicon atoms may contain an SiH group and R 5  and R 6  cannot at the same time represent a hydrogen radcal; Z is a terminating group; u is not less than 5; and the quotient u/v is not less than 0.4. 
     
     
       6. The composition of claim 1 wherein the linear polymer has the formula ##STR27## wherein R 7  is a hydrogen or alkyl radical with 1 to 18 carbon atoms or the --CH 2  OCH 2  CH═CH 2  or --CH 2  OR 8  group and R 8  is an alkyl radical with 1 to 18 carbon atoms or a phenyl radical; u is not less than 5; and the quotient u/v is not less than 0.4.